A tire is structured to include a plurality of rubber members and a plurality of reinforcement members, of which a main material comprises cord. Typically, as shown in FIG. 12, respective parts such as an inner liner 1, a tread 2, side walls 3, rim strips or chafers 4, belt under pads 5, etc. are formed of rubber members conformed to demanded properties and these rubber members are combined with a carcass layer 6, a belt layer 7, a bead body 8, etc., which comprise reinforcement members including cords, to form a tire T. FIG. 11 shows an example of respective constituent members of the tire in an exploded manner.
As shown in FIG. 11, the tread 2 comprises a tread base 2a and a tread cap 2b. Also, the carcass layer 6 comprises first and second carcass plies 6a, 6b and the belt layer 7 comprises a plurality of belts 7a, 7b. The bead body 8 comprises a bead core 8a made of wire or the like, and a filler rubber 8b. The reference numeral 1a in the figure denotes a rubber layer called squeeze and laminated on the inner liner, 6c a ply intermediate tape, and 7c a belt edge tape, both of which comprise a rubber member. The reference numeral 9 denotes a fiber cord filled reinforcement tape wound round the belt layer 7.
Conventionally, there is known as a method of building a tire, which is structured as described above, a two-stage building method of sticking an inner liner, a carcass ply, etc. on a first building drum, which can expand and contract, to build a bead and side walls to make a green case, then transferring the green case to a secondary building drum for having to deform the green case in a troidal shape, and sticking a belt, tread rubber, etc. on the green case to build a green tire.
By the way, in a primary building process and a secondary building process in the two-stage building method, building performed by sticking tire constituent members in one building position in the respective processes leads to lengthening of a building cycle time, which is an obstacle to an improvement in productivity.
In recent years, there has been proposed a system, in which building positions are set respectively and separately every tire constituent member and a building drum or a built body itself built on the building drum is transferred to the respective building positions to permit a predetermined constituent member to be wound round and laminated on the building drum to build a green tire before curing. Further, when respective rubber members such as an inner liner, a tread, etc., or respective reinforcement members such as a carcass layer, a belt layer, etc. are beforehand manufactured in a separate preparation from a tire building process, there is needed a lot of stock, an improvement in productivity cannot be expected, and there is a need for a vast factory space, so that it has been proposed to perform building by spirally overlapping and winding non-cured rubber strips extruded in a ribbon-shaped manner in respective building positions, for example, for respective rubber members according to a tire being built (Patent Documents 1 to 4).
Even in the case where rubber members, which constitute a tire, are built by winding of rubber strips as described above, however, amounts of rubber are considerably varied depending upon the rubber members such that, for example, rubber members such as tread, side walls, etc. are relatively large in volume, a belt under pad, a chafer, etc. are relatively small in rubber volume, and so the larger in rubber volume the rubber members, the longer time required for winding.
Accordingly, in building of a tire, the arrangement of positions for building of the respective rubber members becomes an important factor in relation to time required for winding and building thereof, loss in building cycle time is generated with an ununiform arrangement in respective processes.
Hereupon, the inventors of the present application have thought building respective rubber members by winding of rubber strips as described above, dividing a process of building a cylindrical-shaped carcass band composed of rubber members such as an inner liner, etc. and a carcass ply, a process of subsequently performing bead set, turnup, or the like to build a cylindrical-shaped green case, a process of building a cylindrical-shaped belt/tread band composed of a belt and tread rubber, and a process of uniting the green case and the belt/tread band together to build the same into a final shape, into four building stages, and performing building of respective steps in respective building stages in parallel.
By the way, in building of the carcass band in the building stages, in the case where one building drum is used and rubber members such as an inner liner, a chafer, and a squeeze and respective members such as first and second carcass plies, etc. are wound and built while the building drum is transferred to respective building positions, subsequent building cannot be performed until the built body is conveyed to a subsequent process, so that a building cycle time in the building stages is lengthened and an improvement in efficiency of building cannot be expected.
Also, in building of a belt/tread band in the building stages, in the case where respective members for winding of first and second belts and a reinforcement tape on the belt, for winding of a tread base, which constitutes tread rubber, and rubber strips of a tread cap, and the like are wound and built while the drum is transferred to respective building positions, building cannot be performed until transfer in a subsequent process, so that a building cycle time in the building stages is lengthened and an improvement in efficiency of building cannot be expected. Also, in the case where respective building positions are aligned along transfer sections, to which the building drum is transferred, a total length is lengthened, so that there is a need for a large installation space and transfer to a subsequent process also becomes low in efficiency.    Patent Documents 1: JP-B-6-51367    Patent Documents 2: JP-A-9-29858    Patent Documents 3: JP-A-2002-178415    Patent Documents 4: JP-A-2002-205512